Production of exotic Λ hypernuclei via mesonic beams

Abstract

We study the production of neutron-rich hypernuclei Λ 12 Be, Λ 16 C, and Λ 10 Li by the (π −, K +) and (K −, π +) reactions in flight and treat two different mechanisms of production. The first mechanism is a two-step process with meson charge exchange (e.g., π − p → π 0 n, π 0 p → K +Λ). The other mechanism is one-step production (π − p → K +Σ−) proceeding via a small Σ− component, arising in Λ hypernuclei due to ΛN–ΣN coupling, as a doorway state. Typically, the two-step mechanism is more productive. The forward differential cross section of the 10B(π −,K +) reaction is about 70 nb/sr at an incident momentum of 1.05 GeV/c. On the other hand, the one-step process can serve as a direct measurement of the Σ admixture if the two-step contribution is suppressed by a suitable choice of the reaction kinematics.